The present invention relates to motor-driven tools and, more particularly, to motor-driven multipurpose woodworking tools.
In the design of multipurpose woodworking tools, it is desirable to provide a tool which can be adjusted to perform as many different types of woodworking operations as possible. Often, however, the greater the number of woodworking functions a multipurpose tool can provide, the less each function can be performed efficiently and conveniently by an operator. For example, Parker et al. U.S. Pat. No. 3,282,309 discloses a multipurpose woodworking tool which includes a base, a frame having a pair of parallel way tubes mounted on the base, a headstock mounted on the way tubes and having a motor-driven quill spindle, and a table pivotally mounted on support legs which are adjustably attached to a carriage slidably mounted on the way tubes. This tool is capable of functioning as a table saw, a disc sanding machine, a lathe, a horizontal boring machine, a vertical drill press and an under-the-table shaper.
The vertical drill press and under-the-table shaping functions are made possible by pivot mounts which connect the way tube frame to the base of the tool. When pivoted about one end of the way tube frame, the way tubes are swung to a substantially vertical position so that the headstock is located above the table and carriage assembly. The table, normally oriented parallel to the way tubes, is then pivoted about its support legs to a position in which it faces and is perpendicular to an axis of the quill spindle, and the carriage adjusted in position on the vertical way tubes so that the table is spaced an appropriate distance from the quill spindle. The table can be positioned so that the transverse saw blade seat is in registry with the quill spindle so that a drill bit held by the spindle may pass through the plane of the table.
When the way tube frame is pivoted about the opposite end, the way tubes are again oriented substantially vertically but the headstock is located below the table assembly. To complete the adjustment to the under-the-table shaping mode, the table is pivoted substantially 90.degree. from a position parallel to the way tubes, or 180.degree. for the drill press orientation, in a direction opposite that for the drill press mode, so that the table is perpendicular to and faces away from the quill spindle axis. To complete the adjustment, the carriage is moved toward the headstock so that the quill spindle of the headstock projects upwardly through a transverse slot formed in the table.
In order to pivot the table to a drill press position in which it faces and is perpendicular to the axis of the quill spindle, as required in the drill press mode, it is necessary that the distance from the table slot to a transverse end of the table adjacent the way tubes not exceed the distance from the spindle to the way tubes, so that the slot can be placed in registry with the spindle. Conversely, in order to pivot the table to an under-the-table shaping position in which it faces away from the quill spindle, it is necessary that the distance from the table slot to an opposite transverse end adjacent the carriage not exceed the distance from the quill spindle to the top surface of the carriage, since the quill spindle must protrude through the table slot when the tool is adjusted to perform an under-the-table shaping operation. As a result, in order to provide a multipurpose tool which can perform both vertical drill press and under-the-table shaping functions, these dimensional constraints severely limit the length of a table as measured in a direction parallel to the way tubes.
An attempt to remedy this problem was made in the design of the tool of the Parker et al. patent. That tool included a work table provided with fittings shaped to receive the legs of a table extension. When the work table was pivoted to a position in which it was parallel to the quill spindle, the table extension could be added to increase the effective length of the work surface. However, such an accessory increases the overall expense of the tool, and requires closely toleranced parts to minimize the likelihood that the work surface of the table extension would be positioned slightly above or below the work surface of the work table.
Accordingly, there is a need for a multipurpose woodworking tool capable of performing both vertical drill press and under-the-table shaping functions, and which includes a table assembly which includes a relatively long dimension in a direction parallel to the way tubes, preferably exceeding the relatively small dimensions of a table capable of pivoting 180.degree.. Furthermore, such a table should be relatively simple to adjust, and should not include structure which would greatly increase the overall expense of fabricating the tool.